Project Code: APM-Pressure-Transmitter-2013 ADI Pressure Transmitter Solutions Industrial Pressure Transmitter System Theory and Typical Architecture A pressure transmitter can measure flow rate, pressure, level, and so on. Principles of a pressure sensor used in it, which are the piezoresistance effect type, the capacitance type, and the micro resonator type, are diverse. Diaphragms of a single silicon crystal are used as pressure receiving elements in each type. With a multiple piezoresistive gauge sensor for application to intelligent pressure transmitter, it can measure three quantities (i.e., differential and static pressure and the temperature). In general, a pressure transmitter could be powered by a battery, a line power, or a loop power and consist of power supplies, pressure/temperature sensors, signal conditioning, ADC, processors, display, keyboard, logic I/Os, and multiple communications like 4 mA to 20 mA, HART, RS-485/RS-422/RS-232, PROFIBUS, Modbus, and foundation. Industrial Pressure Transmitter System Design Considerations and Major Challenges To have an appropriate pressure transmitter system design, designers must consider many different system requirements including accuracy, zero drift, temperature, and static pressure compensation. • Characteristic compensation needs to be considered by means of temperature and static pressure signals, in addition to the differential pressure signal. • Preventive maintenance function to detect sensor aging deterioration or any abnormality. • Pressure transmitter product maximum range ability can be as high as 200:1, and the upper limit even up to 15,000 psi. • Measurement accuracy can be high as 0.04% of full-scale range, which often requires a 16-bit to 24-bit analog-to-digital converter. • Connectivity to different field buses like HART, PROFIBUS, Modbus, foundation, RS-485/RS-422/RS-232, wireless HART, and so on. Isolation might be needed between sensors, conditioning circuits, system power supply, communication, and I/O; isolation grade varies from 1 kV to 2.5 kV. • Isolation might be needed between sensors, conditioning circuits, system power supply, communication, and I/O; isolation grade varies from 1 kV to 2.5 kV. • Both battery and loop-powered differential pressure transmitters require carefully selected ultralow power components like MCU, ADCs, and references. Industrial site temperature environments are quite complex, even atrocious. Low temperature drift coefficient and low power consumption are very important for differential pressure transmitters to endure wide working temperature ranges. ADI offers the perfect portfolio of precision amplifiers, precision references, precision analog-to-digital converters, and low power ARM® Cortex™-M3 core microprocessors. Besides that, EMC interference immunity under low power systems is also a big challenge for pressure transmitters, such as surge, EFT, and ESD. High level ESD immunity components offered by ADI greatly help to improve reliability and robustness. In addition, limited space inside the pressure transmitter is requiring dense systems. Therefore, the form factor has to be reduced to accommodate this. Recently, advances in integration have allowed system designers to migrate to smaller, lower power, lower cost solutions, with performance approaching those of larger systems. The challenge moving forward is to continue to drive the integration of these solutions, while increasing their performance and diagnostic capabilities. ADI offers market tailored solutions to aid in the design process. These solutions feature our industry-leading technologies and offer a range of design options—from implementation of discrete components to fully integrated solutions, and everything in between. Total Solutions from ADI ADI’s amplifier, data conversion, signal processing, communications, and power technology and expertise provide leverage for high resolution, low noise, and low power industry pressure transmitter systems. instrumentation.analog.com Signal Chain for Discrete Signal Conditioning BATTERY POWERED OR LINE POWERED OR LOOP-POWERED INTERFACES POWER MANAGEMENT DIFFERENTIAL PRESSURE (MAIN VALUE MEASURED) DC/DC WIRELESS LDO RS-485/RS-422 IN-AMP (PGA) POWER ISOLATION PROFIBUS PROCESSOR STATIC PRESSURE (COMPENSATION) I/O SIGNAL ISOLATION MCU DAC PWM MUX S-D ADC (24-BIT) 4mA TO 20mA VREF TEMPERATURE (COMPENSATION) V/I DRIVER HMI KEYBOARD +125 C o −40oC (Note: dotted line sections may be optional or highly integrated according to various applications.) Note: The signal chains above are representative of the system block diagram of a signal chain for discrete signal conditioning design. The technical requirements of the blocks vary, but the products listed in the table below are representative of ADI's solutions that meet some of those requirements. Signal Chain for Integrated Signal Conditioning BATTERY POWERED OR LINE POWERED OR LOOP-POWERED INTERFACES POWER MANAGEMENT DIFFERENTIAL PRESSURE (MAIN VALUE MEASURED) DC/DC WIRELESS LDO S-D ADC (24-BIT) IN-AMP (PGA) VREF S-D ADC (24-BIT) TEMPERATURE (COMPENSATION) POWER ISOLATION PROFIBUS I/O SIGNAL ISOLATION DAC PWM MUX STATIC PRESSURE (COMPENSATION) PROCESSOR MCU RS-485/RS-422 4mA TO 20mA V/I DRIVER HMI KEYBOARD +125 C o −40oC (Note: dotted line sections may be optional or highly integrated according to various applications.) Note: The signal chains above are representative of the system block diagram of a signal chain for integrated signal conditioning design. The technical requirements of the blocks vary, but the products listed in the table below are representative of ADI's solutions that meet some of those requirements. 2 | ADI’s Pressure Transmitter Solutions Main Product Introduction Device Description Key Features Benefits ADC AD7780/ AD7781 20-bit/24-bit, 1-channel, PGA, sigma-delta ADC Low power 500 μA maximum, 10 Hz to 16.7 Hz, 1 to 128 PGA, p-p resolution over 17 bits Cost very competitive + easy to use AD7787/ AD7788/ AD7789/ AD7790/ AD7791 16-bit/24-bit, 1-channel/ 2-channel, sigma-delta ADC Ultralow power from 80 μA to 160 μA max, 9.5 Hz to 120 Hz, 50 Hz/60 Hz rejection Ultralow power + small package AD7796/ AD7797/ AD7798/ AD7799 16-bit/24-bit, 1-channel/ 3-channel, sigma-delta ADC with PGA Low power 500 μA maximum, 4.17 Hz to 470 Hz, PGA 1 to 128, reference, low noise Low power + highly integrated with PGA ADuCM360/ ADuCM361 Analog microcontroller (ARM Cortex-M3 core) Dual 24-bit Σ-Δ ADC (ADuCM360), single 24-bit Σ-Δ ADC (ADuCM361) programmable ADC output rate (3.5 Hz to 3.906 kHz), 12-bit DAC, programmable current sources, temperature sensor, internal reference, 4 ppm/°C, 16 MHz cortex, 128 kB flash, 8 kB RAM core consumes 290 μA/MHz, power-down mode: 4 μA (wake-up timer active) Ultra low power, high precision, leading integration chip solution ADuCRF101 Embedded ISM band RF transceiver (862 MHz to 928 MHz and 431 MHz to 464 MHz); Cortex-M3 32-bit processor, 16 MHz; 190 μA /MHz, Analog microcontroller (ARM Cortex in active mode; 1.6 μA, in power-down mode, MCU memory and Cortex-M3 with RF transceiver) transceiver memory retained; 128 kB/64 kB flash/EE memory, 16 kB/8 kB SRAM; 6-channel, 14-bit or 12-bit ADC Processor/MCU ADUC7060/ ADUC7061 Analog microcontroller (ARM7TDMI ® core) Ultralow power, highly integrated with both RF transceivers and analog channels 24-bit, 8 kSPS ADC, up to 10 ADC channels; 1-channel, 14-bit voltage DAC outputs; 16-bit, 6-channel PWM; on-chip voltage reference ±10 ppm/°C and temperature sensor; programmable sensor excitation current sources, 200 μA to 2 mA; up to 14 GPIO pins High resolution, low power, and abundant resources AMP AD8422 Instrumentation amplifier Bandwidth = 2.2 MHz; Vos = 0.36 mV ; V NOISE density = 88 nV/√Hz; IB = 1 nA; gain control interface = resistor; IQ = 330 μA; RRO Third-generation AD620 AD8236 Instrumentation amplifier Bandwidth = 23 kHz; Vos = 3.5 mV ; V NOISE density = 76 nV/√Hz; IB = 10 pA ; gain control interface = resistor, Icc = 50 μA Ultralow power and competitive price AD8237 Instrumentation amplifier Bandwidth = 200 kHz; Vos = 75 μV; drift 0.3 μV/ºC; gain error: 0.005%, gain drift 0.5 ppm/ºC; IB <1 nA; single-supply: 1.8 V to 5.5 V; IQ = 150 μA Low offset voltage, zero drift, low power, and cost effective AD8556/ AD8557 Instrumentation amplifier Bandwidth = 2 MHz; Vos = 12 μV; VNOISE density = 32 nV/√Hz; IB = 25 nA; gain control interface = digital Good for fine tuning an analog transmitter AD8276 Difference amplifier Bandwidth = 550 kHz; Vos = 200 μV; VNOISE density = 70 nV/√Hz; low supply Price competitive output solution for analog current: 200 μA maximum per channel, rugged input overvoltage protection interface AD5410/ AD5420 Current source DAC 12-bit/16-bit resolution; 0 mA to 24 mA ±0.01% FSR TUE; ±3 ppm/°C typical output drift; on-chip reference (10 ppm/°C maximum) Universal output DAC and support HART communication AD5421 Current source DAC 16-bit resolution; 3.2 mA to 24 mA; NAMUR-compliant alarm; TUE error: 0.05% maximum; on-chip reference TC: 4 ppm/°C maximum an range: 5.5 V to 52 V Loop-powered universal output DAC and support HART AD5412/ AD5422 Current source and voltage output DACs 12-bit/16-bit resolution; 0 mA to 24 mA ±0.01% FSR TUE; ±10 V with 10% Universal output with both voltage and overrange ±0.01% FSR TUE; on-chip reference (10 ppm/°C maximum) current AD5660 nanoDAC ® Single 16-bit, 5 ppm/°C on-chip reference; tiny 8-lead SOT-23/MSOP packages Tiny package and high performance AD693 Loop-powered sensor transmitter Loop-powered operation, instrumentation amplifier front end, precalibrated 30 mV or 60 mV input spans, precalibrated PT 100 interface, precalibrated output spans, 4 mA to 20 mA unipolar, 12 ± 8 mA bipolar A complete monolithic low-level, V-I, loop signal conditioner DAC instrumentation.analog.com | 3 Main Product Introduction (Continued) Part Number Description Temperature Benefits HART Modem Low power HART modem HART-compliant, fully integrated FSK modem, 1200 Hz and 2200 Hz sinusoidal shift frequencies, 115 μA max in receive mode. Integrated receive bandpass filter, optional clocking configurations, buffered HART output, 2 V to 5.5 V power supply Lowest power, smallest footprint, on-chip oscillator ADR29x Voltage references Initial accuracy: ±0.08% (maximum) maximum temperature coefficient: 8 ppm/°C; supply current 15 μA maximum Super low quiescent current: 15 μA (maximum) ADR3412 Low power reference 1.2 V precision output, supply current: 100 μA max, low noise (<10 Hz): 8 μVp-p typ. Supply range: 2.3 V to 5.5 V, long term stability: 30 ppm/1000 hrs @ 50°C Low power, small package ADuM1100 Single channel digital isolators 2.5 kV rms; very low power operation, 3 V/5 V level translation; high data rate: dc to 100 Mbps (NRZ) Lowest power operation choice ADuM140x Quad channel digital isolators 2.5 kV rms; low power operation, 3 V/5 V level translation; high data rate: dc to 90 Mbps (NRZ), output enable function High data rate: dc to 90 Mbps (NRZ), low power operation ADuM744x Quad channel digital isolators 1 kV rms isolation rating, low power operation; bidirectional communication, Low power operation and competitive price up to 25 Mbps data rate (NRZ), 3 V/5 V level translation ADuM540x Quad channel isolators with integrated dc-to-dc converter IsoPower integrated, isolated dc-to-dc converter, regulated 3.3 V or 5.0 V output, up to 500 mW output power, high temperature operation: 105°C Highly integrated isolation for both signal and power ADuM347x PWM controller and transformer driver with quad channel isolators Isolated PWM controller; integrated transformer driver; regulated adjustable output: 3.3 V to 24 V; 2 W output power; 70% efficiency; quad dc-to-25 Mbps signal isolation channels; soft start function at power-up; thermal shutdown, 2.5 kV rms isolation More than 2 W output capability with good efficiency and 200 kHz to 1 MHz adjustable oscillator frequency ADM2582/ ADM2587E Isolated RS-485/RS-422 Half- or full-duplex, 16 M/ 500 kbps, 5 V or 3.3 V operation Integrated isolated dc-dc ±15 kV ESD ADM2483 Isolated RS-485 transceiver with integrated transformer driver Half-duplex, 16 Mbps, integrated oscillator driver for external transformer, 5 V or 3.3 V operation, 50 nodes on bus Low power operation and competitive price ADM2485 Isolated RS-485 transceiver with integrated transformer driver Half-duplex, 16 Mbps, Integrated oscillator driver for external transformer, 5 V or 3.3 V operation, 50 nodes on bus PROFIBUS compliant TMP05 Temperature sensor ±1°C accurate, 12-bit digital, PWM output interface, operation from 3 V to 5.5 V Small package with competitive price ADT75 Temperature sensor ±1°C accurate, 12-bit digital, SMBus/I2C-compatible interface, operation from 3 V to 5.5 V, over temperature indicator Good performance with competitive price ISM band FSK/GFSK/OOK/ MSK/GMSK transceiver IC Frequency bands, 862 MHz to 928 MHz, 431 MHz to 464 MHz; ultralow power; ISM band, data rates supported, 1 kbps to 300 kbps, single-ended and differential power amplifiers ISM band; data rate 1 kbps to 300 kbps; very low power consumption Multiplexers 4-channel/8-channel, 1.8 V to 5.5 V supply; 3 Ω maximum on resistance, 100 pA leakage current, up to 30 mA continuous current Very low leakage current, cost competitive AD5700/ AD5700-1 Ref Isolator Interface Temp Sensor Wireless ADF7023 Mux ADG759 4 | ADI’s Pressure Transmitter Solutions Main Product Introduction (Continued) Device Description Key Features Benefits Power ADP2441 Step-down dc-to-dc regulator Wide input voltage range of 4.5 V to 36 V, 1 A max, high efficiency of up to 94%, ±1% ACC, adjustable switching frequency. 300 kHz to 1 MHz, external soft start, overcurrent protection Wide input range up to 36 V, high efficiency, small package ADP160 Linear regulator 2.2 V to 5.5 V input, 150 mA load current, 560 nA quiescent current, 195 mV @ 150 mA dropout voltage, PSRR 72 dB @ 100 Hz Extremely low quiescent current, high PSRR, low dropout voltage ADP2108 Switching regulator 5.5 V input, 600 mA, 3 MHz, 18 μA quiescent current, 100% duty cycle, 1 μH inductor, SOT-23 package Tiny solution size, small quiescent current, and high light load efficiency ADP1720 Linear regulator Supply range: 4 V to 28 V, low light load current: 28 μA at 0 μA load, low dropout: 275 mV @ 50 mA, initial accuracy: ±0.5%, enable logic control or logic control enabled, current and thermal overload protection Low power consumption Reference Circuits • Fully Isolated Input Module Based on the AD7793 24-Bit Σ-Δ ADC and the ADuM5401 Digital Isolator (CN0066)—www.analog.com/CN0066 • 4 mA to 20 mA Loop-Powered Temperature Monitor Using the ADuC7060/ADuC7061 Precision Analog Microcontroller (CN0145)—www.analog.com/CN0145 • Simplified 16-Bit, 4 mA to 20 mA Output Solution Using the AD5420 (CN0098)—www.analog.com/CN0098 • Weigh Scale Design Using the AD7781 20-Bit Sigma-Delta ADC with Internal PGA (CN0108)—www.analog.com/CN0108 • Precision Weigh Scale Design Using the AD7791 24-Bit Sigma-Delta ADC with External ADA4528-1 Zero-Drift Amplifiers (CN0216)—www.analog.com/CN0216 • Complete 4 mA to 20 mA Loop-Powered Field Instrument with HART Interface (CN0267)—www.analog.com/CN0267 • Complete 4 mA to 20 mA HART Solution with Additional Voltage Output Capability (CN0278)—www.analog.com/CN0278 • Complete 4 mA to 20 mA HART Solution (CN0270)—www.analog.com/CN0270 • 4 mA to 20 mA Loop-Powered Temperature Monitor Using the ADuC7060/ADuC7061 Precision Analog Microcontroller (CN0145)—www.analog.com/CN0145 • Complete Closed-Loop Precision Analog Microcontroller Thermocouple Measurement System with 4 mA to 20 mA Output (CN0300)—www.analog.com/CN0300 For more needs about pressure transmitters, please contact ADI. Customer Interaction Center Technical Hotline 1-800-419-0108 (India) 1-800-225-5234 (Singapore) 0800-055-085 (Taiwan) 82-2-2155-4200 (Korea) Email [email protected] EngineerZone ez.analog.com Free Sample www.analog.com/sample What ADI Can Provide to Customers • ADC • ADIsimADC—www.analog.com/zh/ADIsimADC • Σ-Δ ADC register configuration assistant— www.analog.com/SigmaDeltaRegisterConfigurationAssistant • DAC • ADIsimDAC—www.analog.com/ADIsimDAC • Amp • ADIsimOpAmp—www.analog.com/ADIsimOpAmp • ADIsimDiffAmp—www.analog.com/ADIsimDiffAmp • Power • ADIsimPower—www.analog.com/ADIsimPower • Processor • Emulation tools and some software instrumentation.analog.com | 5 Analog Devices China Asia Pacific Headquarters 22/F One Corporate Ave. 222 Hu Bin Road Shanghai, 200021 China Tel: 86.21.2320.8000 Fax: 86.21.2320.8222 Analog Devices, Inc. Korea Headquarters 6F Hibrand Living Tower 215 Yangjae-Dong Seocho-Gu Seoul, 137-924 South Korea Tel: 82.2.2155.4200 Fax: 82.2.2155.4290 Analog Devices, Inc. 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